A dental implant system is an artificial tooth root replacement, which is used in prosthetic dentistry to support restorations that resemble a tooth or a group of teeth. An implant system typically includes an implant or base, which is surgically placed in the jaw of a patient, and an abutment or extension, which extends from the implant to support a restoration.
Known implant systems are essentially of two types. Referring to FIG. 1, a first type of implant system 2 in the prior art includes an implant 4, which is placed in a hole bored in the recipient bone, and an abutment 8, which operates as a support for a dental restoration and which may include a metallic interface 6 extending downward to engage implant 4. Implant system 2 also includes a screw-type device 10 engaging abutment 8, abutment interface 6 and implant 4 longitudinally.
A second type of implant system 10 is illustrated in FIG. 2 and includes an implant 12, which is placed in a hole bored in the recipient bone and which has a sloping shoulder 14. Implant system 10 further includes an abutment 13, which supports restoration 16 (shown in the form of a front tooth) and which has a locking taper 18 that is force-fitted into a well in the inner portion of implant 12.
Implants in the prior art (such as those depicted in FIGS. 1 and 2) are generally made from titanium due to the strength and biocompatibility properties of this metal. In addition, titanium can be successfully fused into the surrounding bone when osteoblasts move on and into its surface. This process is generally termed “integration” or “osseointegration” and produces a strong anchoring that prevents an independent movement of the implant.
Unfortunately, metal implants also have a number of drawbacks, which include:
1. Metal implants are mostly made not from pure titanium, but from titanium alloys to improve ease of machining. For example, Grade 5 titanium is sometime employed, which is an alloy that contains aluminum and vanadium. Some of those titanium alloys contain elements that are potentially toxic elements.
2. Metal implants may cause “oral galvanism,” which is a toxic effect caused by a galvanic current generated from the transport of metal ions through the saliva from the implant to another metallic restoration such as a different implant, a filling, a crown or an orthodontic device. As a consequence, the rate of corrosion (or dissolution) of a metal-based restoration is increased, leading to dispersion of metal ions and related oxides in the patient's body and to sensitivity, inflammations, allergies and autoimmune diseases.
3. The attachment of the internal screw (for example, screw 10 of FIG. 1) may fail. The screw may loosen, break, and become a source of bacteria due to manufacturing tolerances between the screw and the implant, leading to a rejection or to a supporting bone failure for the entire implant.
4. Current implant designs include a number of curvatures and recesses that may house bacterial colonies and cause infections and inflammations for lack of access and proper dental hygiene.
5. Metal implants are rigid attachments that are unsuitable for bridging to a natural tooth, which by its nature is slightly mobile. Therefore, there is an inherent incompatibility between a metal implant and a neighboring natural tooth. In some instances, a restoration (for example, an artificial crown) may break due to the inflexibility in the implant.
6. Metal implants are dark in color and tend to show through gum tissue, making them cosmetically unsightly.
7. Metal implants are manufactured and sold in many sizes and the restoring dentist must carry a significant inventory, leading to a sizable monetary investment in implants, abutments, accessories, instruments, etc.
8. The dentist's choice of implant and abutment designs is limited to what is commercially available, limiting the usefulness of the implant and the creativity of the restoring dentist.
In order to decrease rigidity, metal implants have been proposed that include a plastic element providing the abutment with some degree of movement in relation to the implant. Such a plastic element not only adds to the complexity of the implant, but unfortunately tends to fail after a few months of service.
Recent research in dental implantology has focused on the use of zircon dioxide (ZrO2, generally identified in the dental field as zirconia) for the manufacture of dental implants. Zirconia is a high-strength ceramic material that can be milled to shape in a dentist's office using especially designed CAD-CAM machines. In addition, zirconia is highly biocompatible and is more cosmetically pleasing due to its bright, tooth-like color.
The designs of zirconia implants and abutments that have been proposed to date are essentially based on existing metal implant designs. In particular, no implant and abutment designs have been proposed that maximize the properties of zirconia and that resolve or at least minimize the drawbacks associated with current metal implant systems.
Therefore, it would be desirable to provide a dental implant system that is made entirely from zirconia and that maximizes the properties of zirconia.
It would also be desirable to have a dental implant system that is made with a reduced number of components than implant systems of the prior art.
It would further be desirable to have a dental implant system that can be custom-milled to shape in a dental office or at an outside dental lab.
It would further be desirable to have a dental implant system having contours that minimize the risk of bacterial infections and that are adaptable for use in different positions within the mouth of the patient, for example, in the front area of the mouth.
It would further be desirable to have a dental implant system that allows some degree of movement to the supported restoration in a manner similar to natural teeth.